A drawback of these stoppers is that, when the cap and the bottle are rigid, it is not possible to absorb the manufacturing play, which is relatively great in the case of glass bottles. Thus, the limit of screwing is fixed by the end of the screw threads of the bottle and of the cap, which must permit an end of screwing before the cap comes into contact with the bottle. As a result, there is an unattractive gap between the base of the cap and the bottle.
This problem of course does not exist when the cap is provided with a deformable skirt which comes to bear against the bottle before the screwing is completed. But such caps with deformable skirt are delicate and costly to manufacture, and have a limited lifetime by use of plastic materials sensitive to oxygen, heat, and light. They moreover have an inelegant appearance.